1. Field of the Invention
The present invention relates to a nuclear radiation detection system for monitoring movement of nuclear material across a perimeter defined by scintillator fiber sensor which forms a line detector over a length of many meters in the monitored area.
2. Prior Art
Previously, nuclear detectors have been comprised of gas-filled detectors used for gamma ray detection. Conventional nuclear detectors comprise Geiger-Mueller tubes, Sodium Iodide (NaI) scintillators, and Germanium drifted Lithium (Ge/Li) detectors, However, these type detectors are point sensors which measure radiation at low levels only in the immediate vicinity of the source and cannot readily be used in the remote and covert detection of nuclear sources moved across the perimeter of a monitored area. For the dectors to be covert, they would need to be installed on the side of a road at a suitable shielded or protected area. Therefore, the distance between a radiation source transported on the road and the detector becomes excessive. These detectors also have electronics directly associated therewith. This combination results in a relatively large device which cannot easily be hidden and is also susceptible to electromagnetic interference (EMI), dirt, vibrations, etc.
The Lithium drifted Germanium detectors must be continuously stored and operated at cryogenic temperatures in order to preserve the Lithium profile, a complexity that rules out the use of this detector for clandestine operation.